Russian Sergey Kirdyapkin will be stripped of the 50km walk gold medal he won at the 2012 London Olympics after the Court of Arbitration for Sport (CAS) upheld an appeal by the IAAF against the Russian anti-doping agency (RUSADA).

The sport's governing body (IAAF) appealed on six cases where they said RUSADA had been "selective" in annulling previous results of the athletes after they were banned for irregularities in their biological passports.

CAS upheld all six appeals.